The Open Mobile Alliance (OMA) data synchronization and device management protocols define a process of exchanging commands between a mobile device and a server. Such commands are grouped together into messages. eXtensible Markup Language (XML) is used to represent the commands and messages. The size of a message, represented as a valid XML document, is limited either by the transport, such as short messaging service (SMS), object exchange (OBEX), or hypertext transfer protocol (HTTP), or by the memory available on either the device sending the message or the device receiving the message. One approach is to assemble the entire message in memory and then send the assembled message over the transport layer. This approach is acceptable in cases where the transport imposes a message-size limitation, although in practice this size limitation can be much larger than the available memory on the device. Therefore, this approach is inefficient if the message-size limitation is imposed by the memory of the transmitting device, because a larger number of messages must be exchanged over the transport, which prolongs the session. For example, in any TCP/IP based transport such as HTTP, connection establishment accounts for most of the time in a single message exchange.
U.S. Patent Application Publication No. 20040006741A1 published in the names of Radja et al on 8 Jan. 2004 and entitled “System and method for efficient processing of XML documents represented as an event stream” describes a system and method for processing a representation of an XML document to create a sequence of contiguous bytes for transfer from a source to a destination. The representation of the XML document is parsed into a set of information items. A relationship among the information items is determined from the representation of the XML document. An operation code is assigned to each information element based upon the determined relationship, where each assigned operation code defines how the associated information should be interpreted at the destination. The operation codes and information items are formed into a sequence of contiguous bytes suitable for transfer from the source to the destination, where the byte sequence does not depend upon any memory address assigned to the byte sequence.
Wong, E Y C, Chan A T S, and Hong V A, “Xstream: a middleware for streaming XML contents over wireless environments”, IEEE Transactions on Software Engineering, V 30, N 12, December 2004, pp. 918-35, describes transcoding and augmentation of a source XML document in a wireless environment. A middleware, XML Streaming (Xstream), is proposed for streaming XML contents over a wireless environment by leveraging rich semantics and structural characteristics of XML documents and by flexibly managing units containing fragments of data into autonomous units, known as Xstream Data Unit (XDU) fragments. By fragmenting and organizing an XML document into XDU fragments, fragments can be incrementally sent across a wireless link, and the receiver can look-ahead process the document without having to wait for the entire document to be downloaded. The fragmenting strategy is based on the wireless link's Maximum Transfer Units (MTUs). A collection of XDUs are grouped into a packet to optimize packet delivery and processing using packetizing strategies. At the receiver, a reassembly strategy reconstructs the XML document as XDU fragments are received. This article presents a mechanism for transmitting only a specific fragment of an XML document and defines a mechanism to provide context information for a recipient to identify the XML fragment.
U.S. Patent Application Publication No. 20040148375A1 published in the names of Levett et al on 29 Jul. 2004 and entitled “Presentation service which enables client device to run a network based application” describes a presentation server that permits a client device to run a network-based application by sending structured data from various data sources to software on the client device. The client device has three layers. The first layer is a communications layer to send and receive messages over the network. The second layer is a database layer to store and allow querying of the structured data. The third layer is a rendering layer that generates data for a user interface from the structured data in the database layer. The client software is self-contained for providing the entire communications, data storage and rendering resources needed to run the network-based application on the client device.
U.S. Patent Application Publication No. 20040138787A1 published in the names of Ransom et al on 15 Jul. 2004 describes a power management architecture for an electrical power distribution system. The power management architecture contains various intelligent electronic devices (IED) distributed throughout the power distribution system to manage the flow and consumption of power from the system. A set of data to be communicated over the network as an XML document is generated. The data is transformed into an XML format as the data is generated, and the XML formatted data is communicated over the network. The process of transforming and communicating are repeated until the entire set of data has been communicated. Each IED is capable of incrementally generated or consuming communicated XML documents containing power management data without having to buffer the complete XML document in memory before, during or after processing. Thus, while XML fragments are aggregated in a buffer, the buffer only flushes once the entire document is assembled. This is a standard mechanism followed by any buffer output stream.
Davis, S J, and Burnett, I S, “Exchanging XML multimedia containers using a binary XML protocol” 2005 IEEE International Conference on Multimedia and Expo, 6-8 Jul. 2005, Amsterdam, Netherlands, describes an alternative to XML and a protocol for independent fragment access). The article states that XML is verbose and transmitting the large files can be wasteful in bandwidth and in power-limited mobile applications. A Remote XML Exchange Protocol (RXEP) is introduced that combines XML compression with a fragment access protocol. RXEP exchanges essential information while minimizing superfluous XML content transmission, making XML containers attractive for multimedia content delivery. The article proposes an encoding format for an XML document and presents a protocol to access fragments.
Thus, a need exists for a method that more efficiently exchanges messages over a transport layer of a communications network.